The RIDGID 3-Layer fine dust replacement filter features 3 layers of filtering material that captures particles too small to be seen by the naked eye. The pleated design offers a large surface area to trap superfine dust and dirt. Captures 99% of all particles 1/2 micron and larger Great for picking up cold fireplace ash, fine dust and everyday dirt Fits RIDGID vacuums 3 to 4.5 gallons Fully washable and reusable 3 Layers of filtering material that captures particles too small to be seen by the naked eye.